Disk drives are often used to record data onto or to reproduce data from a recording media. A disk drive can include a rotating magnetic disk and a head actuated over the disk to magnetically write data to and read data from the disk. The disk includes a plurality of radially spaced, concentric tracks for recording user data.
The storage device industry is always trying to increase the recording density of the disk, or in other words, the amount of data that can be stored in a given area on the disk. Shingled magnetic recording (SMR) has recently been introduced as a way of increasing the number of tracks per inch (TPI) by making the tracks narrower. Since it is technologically easier to read narrow tracks than to write narrow tracks, SMR increases TPI by using a relatively wide shingle write head with a stronger magnetic field to overlap tracks like roof shingles. The non-overlapping portion then serves as a narrow track that can be read by a narrower read head.
One problem encountered with disk drives incorporating SMR technology involves wide area track erasure (WATER). WATER results in data being erased from adjacent tracks near a track being written due to interference from the magnetic field of the write head. The problems caused by WATER are exacerbated when tracks are repeatedly rewritten. In addition, disk drives using shingled write heads are ordinarily more susceptible to WATER than conventional disk drives due to the combination of narrower tracks and a wider shingle write head having a stronger magnetic field.